Werner and Schmidt, J. Labelled Comp., 5,200 (1969) describe the preparation of tritiated cocaine. As a by-product of this reaction they identified tritiated benzoylecgonine by thin layer chromatography. The total specific activity of all by-products before separation was 820 .mu.Ci/mg. Thus the specific acitivity of the by-product tritiated benzoylecgonine was substantially less than that required in a radioimmunoassay.
Bosin et al, Res. Comm. Chem. Path. Pharmacol., ll, 405 (1975) described O-(chlorobenzoyl)ecgonine and O-(m,m-dichlorobenzoyl)ecgonine as intermediates in preparing deuterated benzoylecgonine and cocaine.